Tractor



TRACTOR Filed May 26 1920 2 Sheets-Sheet l E. E. WICKERSHAM May 15, 1923.

May 15, 1923.

E. E. WICKERSHAM TRACTOR Filed May 26 1920 2 Sheets-Sheet 2 v17 lmm m EM QM": W0

WI TN E 55 fidjmmu ,IN V ENTOR EE-mduens'm BY 0% L W a ATTORNEY Patented May 15, 1923.

UNITED STATES PATENT OFFICE.

ELKEB E. WICKERSHAM, OF STOCKTON, CALIFORNIA, ASSIGNOR TO THE HOLT MANU- FACTURING COMPANY, OF STOCKTON, CALIFORNIA, A CORPORATION OF CALI- FORNIA.

TRAUI'OR.

Application filed Kay 28, 1920. Serial No. 384,844.

To all whom it may concern:

Be it known that I, ELMER E. WICKER- BHAM, a citizen of the United States, and a resident of Stockton, county of San Joaquin, and State of California, have invented certain new and useful Improvements in Tractors, of which the following is a specification.

ThlS invention relates to tractors and more particularly to that type of tractors having endless traveling tracks or tread members.

Tractors of the endless belt type usually 'involve side frames mounted to oscillate vertically on the sides of the main frame of the tractor and ordinarily springcushioned means are interposed between the oscillating side. frames and the main frame of the vehicle to form a yielding action as between the main frame and the side tracks and their frames.

In the above form of construction there is no ualization of the load of the vehicle upon the side frames and their belts or treads and the tractors are not efiiciently operative over side bills or uneven roadways for the reason that one or the other of the'side belts or tracks will be subjected to the greater portionof the weight of the vehicle.

It is one of the objects of the present invention to improve the construction of the above general character of tractors so that the can be efiiciently operated on side hills an so that the load will be equalized or compensated.

A further object of the invention is to provide a sim is, substantial, eflicient and racticable and com ensating device directy connectin the si e frames so as to equalize the 10a of the frame carried by the interposed compensating means.

The invention possesses other objects and features of advant e, some of which, with the fore ing, wilfie set forth in the following escription of the referred form of my invention which is 1 lgstfrated 1n the drawings accom an in an orming part of the s cificati dn It is to be understood that I 0 not limit myself to the showing made by. the said drawings and descrl tion, as I may adopt'variations of the pre erred form within the scope of my inventlon as set forth in the claims.

Referring to the drawings:

Figure l is a side elevation showing conventionally one form of tractor to which the invention is applied.

Figure 2 is a transverse section showin the main frame and the connected side track frames in a normal or horizontal running position when traveling on a level surface.

Figure 3 is a similar section showing the actlon of the side frames with their tracks when the vehicle is operating over an am even surface.

The invention is shown, as combined with a form of tractor having a main frame 2, with a suitable motor 3 at its front portion, and at the rear end of the frame there is provided a transverse axle or shaft 4 to which power is transmitted by a suitable mechanism not necessary to be here described as\it forms no part of the present improvement. The front end of the frame is supported on a steering or caster wheel 5 operatively connected to the manual steering wheel 6 shown as arranged on the rear end of the tractor frame adjacent to the drivers seat.

On the outer end of the rear axle or shaft 4 at each side of the main frame there is provided a suitably shaped and constructed track or tread bearing frame 10 over the periphe of which there travels respective endless elt or tread members 11 constructed and arranged to be enga ed and driven by the respective sprocket wieels 12 of which there is one on each end of the shaft 4 and which sprocket wheels 12 are driven b respective ginions 13 forming a part of t e drive mec anism of the tractor.

The perimeter of the frame 10 of each belt or tread is shown as provided with races 14, and in opposition to these races 14 there are provided on the inner surface of the elements, constitutin the endless track or tread, co-ordinate ba races 15 and between the ball races 14 and 15 there are arranged sets of anti-friction .bearings or balls 16. However it is to be understood that the present invention isnot to be lim-- ited to use in connection with ball-bearing treads or tracks as it is equally eflicient with other types of mountings of endless traveling belts for tractors.

It has hfretofore been the practice in the constru tion of tractors. with a pivoted side frame carrying a traction belt or tread to transmit a part of the load of the vehicle frame to the frames by means of resilient cushions interposed between the main frame and side swinging frames but it is n ell known that this does not effectively equalize or distribute the weight of the load to the traction belt and it is to that end that the present invention is evolved and provides means for equalizing or compensating the load on the traction members irrespective of the oscillations of the side frames, and one form of such compensating means is described with respect to the illustrated embodiment of the invention.

As shown in Figure 1, the rear ends of the side frames 10, are pivotally mounted on the outer ends of the axle 4 and the forwardl extending portions of each of the side rames are designed to oscillate vertically in accordance with obstructions or the undulations of the surface over which the vehicle may be traveling.

In the present invention the forward swinging ends of each of the side frames are efi'ectively connected together by suitable means so that when there is a tendency of one of the side frames to swing upwardly on its pivot, a part ofthe increased load to which the upwardly swinging frame is subjected is transmitted by the connecting means to the opposite side frame and therefore the load is equalized at all times during the operation of the tractor.

Though such transversely extending connecting means may be ofany suitable type of construction and arrangement it is 'shown in Figures 2 and 3 as comprising a substantial, flexible element in the form of a sprocket chain 20passing transversely below the body or main frame 2, and thence outwardly and upwardly with the ends connected as at 21 to suitable parts 22 provided on the upper portions of each of the side frames 1,0 and from this it will be seen that a tendency of u ward movement of one of the frames resu ts in a downward pulling movement in the opposite frame due to the transverse connecting means. l/Veight of the frame 2 and its load is transmitted to the transverse member 20 which constitutes therefore, substantially, a carrier or saddle and it is shown as engagin suitable guidemeans 'hereconstituting idler wheels or sprockets 23 provided in suitable bearings or downwardly extending brackets 24: below the side members of the main frame 2 and at such positions as to pert the outwardly and upwardly extendin ends oi the sprocket chain 20 to. free y run u ardly and downwardly and in either irection across the width of the frame.

'lhe journals of the sprocket wheels or guide rollers 23 may be yieldingly supported with respect to the frame 2 or rigidly as desired but in either event the load subjected to the saddle forming member 20 would be. equally transmitted to the side traction carrying frames 10.

In Figure 2 the side frames with the main frame 2 are shown as resting upon a substantially flat or horizontal surface with the bottom portions of the tread belt resting upon a substantially even view the brackets 24 in which the wheels 23 are provided are shown as rigidly connected to the main frame 2. In Figure 3 the vehicle is shown as disposed and operating over an inclined surface with the result that one of the side frames 10 is in an elevate position While the opposite side frame is depressed relatively thereto and clearly showing'how the load is transmitted by the connectin saddle forming part 20 equally to the si e bearing members 10. In Figure 3 the parts 24 in which the idler or guide wheels 23 are arranged are shown as yieldingl connected tothe main frame 2.

T e yielding action of the Figure 3 may be secured as by springs 25 arranged between the frame 2 and the brackets 2a which are pivoted as at 26 to the frame.

llt is understood that the parts may be variously arranged, constructed and formed in the adaptation of the invention to a given structure within the spirit of my invention and the scope of the appended claims.

l-claim:

r 1, In a tractor, a main frame, a self-laying track unit at each side thereof, including a truck frame pivotally connected to the main frame for rocking movement in a vertical plane, and an equalizing suspension means etween each tr'uck frame and the main frame, comprising a flexible member connected to opposite truck frames and passing slidabl beneath the main frame.

2. T e combination set forth in claim 1, including anti-friction devices on the main frame against which the flexible member operates.

3. The combination set forth in claim 1, including anti-friction devices on the main frame under which the flexible member. passes, and springs interposed between the anti-friction devices and the main frame.

4:. In a tractor, a main frame, a self-laying track unit at each side thereof, including a truck frame pivotally connected at its rear end to the ain frame for rocking move ment in a vertical plane, and a chain connected to opposite truck frames at the forward ends of the latter assing slidably beneath the main frame or suspending the weight of the latter equally upon the truck frames.

'5. in a vehicle of the self-laying track plane and in this brackets 24 of type including a body or frame and a truck In testimony whereof I have hereunto set mechanism plvotally connected thereto at my hand in the presence of two subscribing each side for rocking movement in a vertiwltnesses. cal plane, equalizing suspension means com- ELMER E. WIGKERSH. 5,prising a flexible member connected at its Witnesses:

ends to the truck mechanisms and slidably JOHN H, HERBING, engaging the body or frame. v DEE. 

